北疆地区辣椒上烟草花叶病毒（TMV）各分离物的差异性研究

以ＴＭＶ－ｏｍ为对照,测定了辣椒上５个烟草花叶病毒分离物Ｐ－９、Ｐ－３８、Ｐ－４４、Ｐ－７１、ＴＭＶ－ｗｙｍ在４２个辣椒品种、品系上的致病反应,结果表明这５个分离物对辣椒的致病性存在明显差异：Ｐ－７１、ＴＭＶ－ｗｙｍ＞Ｐ－９＞Ｐ－３８、Ｐ－４４;对接种过５个ＴＭＶ分离物的辣椒（四平头）进行过氧化物酶（ＰＯＤ）和酯酶（ＥＳＴ）同工酶分析,结果表明辣椒上５个ＴＭＶ分离物引起的酶活性有差异：导致ＰＯＤ上活性强弱为ＴＭＶ－ｗｙｍ＞Ｐ－９、Ｐ－３８＞Ｐ－４４、Ｐ－７１;引起ＥＳＴ活性强弱为Ｐ－３８＞ＴＭＶ－ｗｙｍ、Ｐ－４４＞Ｐ－７１＞Ｐ－９。说明北疆地区辣椒上ＴＭＶ存在着分化。     

10株葡萄源丝状真菌分离鉴定及其致病力分析

采用组织分离法从京郊地区腐烂的葡萄果实及葡萄叶上分离到10株丝状真菌,其中从腐烂的葡萄果实中分离到3株丝状真菌,命名为814#、815#和880#；从葡萄叶上分离到7株丝状真菌,命名为794#、797#、798#、811#、902#、903#和1397#。结合形态学特征及真菌rDNA ITS区序列分析结果,菌株814#为茎点霉(Phoma sp.),菌株815#为刺孢曲霉(Aspergillus aculeatus),菌株880#为灰葡萄孢(Botrytis cinerea),菌株794#为日本曲霉(Aspergillus japonicus),菌株797#为粉红单端孢(Trichothecium roseum),菌株798#为大蒜盲种葡萄孢(Botrytis porri), 菌株811#为果生炭疽菌(Colletotrichum fructicola),菌株902#为链格孢菌(Alternaria eichhorniae),菌株903#为芬芳镰孢菌(Fusarium redolens)和菌株1397#为脉孢菌(Neurospora terricola),其中A. aculeatus、A. japonicus、C. fructicola、A. eichhorniae、F. redolens和N. terricola未见在葡萄上分离到的报道。将10株丝状真菌分别接种到健康的葡萄、圣女果、苹果和梨果实上,B. cinerea、A. japonicus、A. aculeatus、T. roseum、B. porri、C. fructicola、A. eichhorniae和F. redolens均可使4种果实发病,其中B. cinerea、A. japonicus、B. porri和F. redolens致病力较强；而Phoma sp.和N. terricola只能使葡萄和圣女果发病。     

运动性气单胞菌分离和鉴定方法的研究

通过碱性蛋白胨水 (APW)的增菌效果与气单胞菌培养基 (RYAN)的选择性效果试验 ,建立了运动性气单胞菌细菌学分离和鉴定的实验室检测程序。应用该程序对 8个模拟阳性样品和 71个动物产品、养殖水样及动物病料进行检测 ,结果模拟感染菌全部被分离到 ,从 71个检测样品中分离到 2 0株运动性气单胞菌。实验表明 ,所建立的分离和鉴定方法简便、快速、敏感。此外本文对用生化特性判定细菌致病力的可行性作了探讨     

鸡源致病性大肠杆菌的分离鉴定及药敏试验

为了解鸡源致病性大肠杆菌的生物学特性和耐药性,试验通过采集病料、细菌分离培养、16S rRNA基因鉴定、致病性试验、药敏试验等方法。结果表明:分离出的20株细菌的培养特征、镜检特征均符合大肠杆菌特征;16S rRNA基因序列经BLAST比对与大肠杆菌同源性达99.9%～100%,确定20株分离菌为鸡源大肠杆菌;20株大肠杆菌的致病力为40%～100%;10株鸡源致病性大肠杆菌对15种抗菌药物均呈现多重耐药,耐药率为33.3%～93.3%,耐药情况较严重和复杂。     

Lactoferrin and Its Derived Peptides: An Alternative for Combating Virulence Mechanisms Developed by Pathogens

Due to the emergence of multidrug-resistant pathogens, it is necessary to develop options to fight infections caused by these agents. Lactoferrin (Lf) is a cationic nonheme multifunctional glycoprotein of the innate immune system of mammals that provides numerous benefits. Lf is bacteriostatic and/or bactericidal, can stimulate cell proliferation and differentiation, facilitate iron absorption, improve neural development and cognition, promote bone growth, prevent cancer and exert anti-inflammatory and immunoregulatory effects. Lactoferrin is present in colostrum and milk and is also produced by the secondary granules of polymorphonuclear leukocytes, which store this glycoprotein and release it at sites of infection. Lf is also present in many fluids and exocrine secretions, on the surfaces of the digestive, respiratory and reproductive systems that are commonly exposed to pathogens. Apo-Lf (an iron-free molecule) can be microbiostatic due to its ability to capture ferric iron, blocking the availability of host iron to pathogens. However, apo-Lf is mostly microbicidal via its interaction with the microbial surface, causing membrane damage and altering its permeability function. Lf can inhibit viral entry by binding to cell receptors or viral particles. Lf is also able to counter different important mechanisms evolved by microbial pathogens to infect and invade the host, such as adherence, colonization, invasion, production of biofilms and production of virulence factors such as proteases and toxins. Lf can also cause mitochondrial and caspase-dependent regulated cell death and apoptosis-like in pathogenic yeasts. All of these mechanisms are important targets for treatment with Lf. Holo-Lf (the iron-saturated molecule) can contain up to two ferric ions and can also be microbicidal against some pathogens. On the other hand, lactoferricins (Lfcins) are peptides derived from the N-terminus of Lf that are produced by proteolysis with pepsin under acidic conditions, and they cause similar effects on pathogens to those caused by the parental Lf. Synthetic analog peptides comprising the N-terminus Lf region similarly exhibit potent antimicrobial properties. Importantly, there are no reported pathogens that are resistant to Lf and Lfcins; in addition, Lf and Lfcins have shown a synergistic effect with antimicrobial and antiviral drugs. Due to the Lf properties being microbiostatic, microbicidal, anti-inflammatory and an immune modulator, it represents an excellent natural alternative either alone or as adjuvant in the combat to antibiotic multidrug-resistant bacteria and other pathogens. This review aimed to evaluate the data that appeared in the literature about the effects of Lf and its derived peptides on pathogenic bacteria, protozoa, fungi and viruses and how Lf and Lfcins inhibit the mechanisms developed by these pathogens to cause disease.     

亚砷酸制剂研究进展

针对近年来世界上许多国家或地区相继报道长期暴露于含砷饮用水中的个体出现不同程度的砷中毒症状,或因砷而引起的多种疾病等状况;而我国中医却应用砷剂治疗多种血液肿瘤和实体瘤,特别是治疗急性早幼粒白血病(APL)已取得了较好疗效.从治病性和致病性两个角度分别讨论了主要包括亚砷酸在内的多种含砷化物的生物学毒性,对人体各系统的损害和抗肿瘤作用,为临床应用含砷制剂治疗癌症提供借鉴,同时展望了砷制剂的临床应用前景.     

湿度对交织顶孢霉孢子萌发及对六星黑点豹蠹蛾致病力的影响

测定在不同湿度下对交织顶孢霉(Acremonium implicatum(Miller et al.)Gams)孢子萌发率及对六星黑点豹蠹蛾(Zeuzera leuconotumButler)幼虫的致病力的影响.结果表明:随着相对湿度的增大,孢子萌发速度、萌发率也增高.相对湿度为100%时,72 h孢子萌发率达到90%以上,相对湿度低于75%时,孢子萌发明显受到抑制.在相对湿度为(95±5)%时,交织顶孢霉对六星黑点豹蠹蛾幼虫的致死效果最好,校正死亡率和僵虫率分别为90.04%和70.00%,此时的致死速率也最快,致死中时(LT50)为6.368 d;相对湿度低于(65±5)%时,六星黑点豹蠹蛾幼虫校正死亡率和僵虫率显著降低,LT50均在20 d以上.     

嗜水气单胞菌毒力与毒力基因分布的相关性

采用PCR扩增的方法对9株鱼源嗜水气单胞菌AEROM ONAS HYDROPHILA中的气溶素基因(AERA)、溶血素基因(HLYA)和丝氨酸蛋白酶基因(AHPA)进行了扩增。结果表明,6/9的A.HYDROPHILA中存在AERA基因,8/9的A.HYDROPHILA中存在HLYA基因,而在7/9的A.HYDROPHILA中检测到AHPA基因。通过比较基因检测的结果与嗜水气单胞菌对鲫鱼的致病性,发现AHPA阴性菌株是无毒株,强毒株都呈AERA HLYA AHPA 基因型。AERA HLYA AHPA 基因型是致病性嗜水气单胞菌主要的基因型。本研究首次发现AHPA阳性的嗜水气单胞菌皆为毒力菌株,并且发现AERA和AHPA基因存在相关性,探讨了嗜水气单胞菌致病性与毒力基因分布的关系。     

Anti-Quorum Sensing and Anti-Biofilm Activity of Pelargonium × hortorum Root Extract against Pseudomonas aeruginosa: Combinatorial Effect of Catechin and Gallic Acid

HPLC-UV was used to compare the major constituents of two Pelargonium × hortorum cultivars and Pelargonium sidoides root extract. It revealed the presence of catechin and gallic acid in high concentrations and the absence of umckalin in P. × hortorum root extracts. The antibacterial activity of these extracts was screened against 19 Pseudomonas aeruginosa clinical isolates. P. × hortorum root extracts showed the lowest MIC values (512–1024 µg/mL). This activity was concluded to be attributable to the high concentrations of catechin and gallic acid. The anti-biofilm activity of catechin, gallic acid, and their combination was examined by a crystal violet assay. The combination reduced the percentage of strong and moderate biofilm-forming isolates from 52.63% to 5.26%. The impact on lasI and lasR genes expression using qRT-PCR and simultaneous docking against LasR protein was explored. The combination downregulated lasI and lasR gene expression in eight and six P. aeruginosa isolates, respectively, and showed the greatest docking score. Additionally, the in vivo protection capability of this combination in infected mice showed enhancement in the survival rate. Our study revealed the potential biofilm and quorum-sensing-inhibitory activity of the catechin and gallic acid combination as a novel alternative to inhibit bacterial pathogenicity.     

臭鼻克雷伯氏菌对试验动物致病力的初步研究

研究了臭鼻克雷伯氏菌对几种试验动物的致病力，证实该菌可引起鸭、鸽、小白鼠发病死亡，并使大白鼠、雏鸡等感染带菌，人工培养连续传代后，其毒力随英膜丧失而减弱。